1,2,3,4-Tetrachlorohexafluorobutane in which all of hydrogen atoms bonded to carbon atoms are substituted with chlorine atoms and fluorine atoms is, as described above, a compound which is important as, for example, a synthetic raw material etc. for hexafluoro-1,3-butadiene attracting attentions as a finely processing etching gas for semiconductors.
A process described in the following patent document has so far been known as a production process for 1,2,3,4-tetrachlorohexafluorobutane.
A process for producing 1,2,3,4-tetrachlorohexafluorobutane by reacting a compound represented by CC1X1X2—CC1X3—CC1X4—CC1X5X6 obtained by reacting, for example, CX1X2═CX3—CX4═CX5X6 (X is a hydrogen atom or a fluorine atom) with chlorine, with fluorine in a liquid phase is described in Japanese Patent Application Laid-Open No. 2006-342059 (patent document 1). It is described therein that when 1,2,3,4-tetrachlorohexafluorobutane is used as a common solvent in chlorination reaction and fluorination reaction, an advantage is obtained that it is unnecessary to separate the solvent from the product, so that it is particularly preferred. However, chlorination reaction and fluorination reaction have to be individually carried out in the above reaction. Accordingly, reaction apparatuses and operations for carrying out two processes are required in the process described in the patent document 1, and a problem is involved therein in terms of a cost.    Patent document 1: Japanese Patent Application Laid-Open No. 2006-342059